More middle-class voters regard themselves as leftwing than do working-class voters, and working-class people show less support for overseas aid and immigration than middle-class voters, according to a new YouGov poll, commissioned by Progress, the Labour pressure group.

The findings arguably underline the complex challenge Ed Miliband faces in reconnecting with people who were once described as Labour's core supporters.

"Likewise with overseas aid: middle-class voters divide evenly on whether to end it altogether, while working-class voters back the idea by two-to-one."

On welfare reform, the picture is more nuanced. Overall, middle-class voters show 53% to 38% in favour of reducing welfare benefits for the unemployed, but working-class voters came out 45% to 40% against the idea.

However, skilled workers, as opposed to those with unskilled jobs or relying on state benefits (DEs), are as keen on reducing benefits as the ABs and C1s; it is the DEs who come out against the idea. This policy is also supported in every region except the north of England and Scotland.

Kellner concludes: "Opposition to lower benefits is greatest among those who most fear losing out, or are currently relying on state benefits – scant sign there of working-class solidarity."

The polling, based on aggregate data compiled in the summer and autumn, shows proportionately more middle-class people (36%) describe themselves as leftwing than working-class (28%).

Far more DE voters disown any political affiliation.

The results lead Kellner to conclude that although working-class voters are still more likely to vote Labour than Conservative, this has more to do with tribe and tradition, than ideology or policy.

He is more broadly a strong advocate of the view that Labour will win from the centre.

The polling also shows working-class voters regard stopping immigration as the single most important of seven policies put to them.

Among C2 and DE voters a ban on all immigration is supported by 67% to 26%. Among middle-class voters (ABC1 voters) support is evenly divided with 49% to 46% opposed. On ending all overseas aid, the proposition is supported by C2 and DE voters by 58% to 31% and opposed by AB voters by 48% to 47%. On reducing welfare benefits to the unemployed ABs support the measure by 53% to 38% and C2s by a similar margin of 52 to 33%. Only DEs oppose the measure by a considerable 56 to 29%.

Across the classes there is uniform opposition to income tax increases to protect public services. There is also general opposition to spending cuts.

There is little class difference in overall support shown for gay marriage, nationalising the rail companies or putting workers on company boards.

Progress director Robert Philpott said: "These results show the need for Labour to avoid sectional appeals targeted at specific classes. As it did in the runup to 1997 election, the party needs to develop policies and a message that can appeal across a broad cross-class coalition. Ed Miliband's notion of one nation Labour offers the opportunity to do just that."